The account owner can close the company from the Company menu. It is hidden at once, and deleted for good after 30 days (or straight away from the Trash).
From your Settings you can delete your login: you are removed from every project you were invited to, and your login is deleted. If you are the only owner of a company, hand it over or close it first. Time you recorded is kept for the company’s records, shown as a former member.
Billing records for up to 7 years, and safety records for as long as workplace health and safety law requires. Questions: support@tatasque.com.